CVE-2025-39713

Kernel buffer overflow via unlocked length check

Published Sep 5, 2025 · Updated Sep 5, 2025

A TOCTOU race in the rainshadow-cec driver in Linux allows local users to overflow a kernel buffer through concurrent interrupts. The rain_interrupt() handler checks rain->buf_len before taking rain->buf_lock, while rain_irq_work_handler() changes the same length under that lock, so racing interrupts can increment the length past DATA_SIZE. Exploitation requires low-privileged local access and winning a high-complexity race; the published assessment limits the consequence to service interruption.

CVSS severity4.7
Medium
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A TOCTOU race in the rainshadow-cec driver in Linux allows local users to overflow a kernel buffer through concurrent interrupts. The rain_interrupt() handler checks rain->buf_len before taking rain->buf_lock, while rain_irq_work_handler() changes the same length under that lock, so racing interrupts can increment the length past DATA_SIZE. Exploitation requires low-privileged local access and winning a high-complexity race; the published assessment limits the consequence to service interruption.

The record

CVE
CVE-2025-39713
Published
Sep 5, 2025
Updated
Sep 5, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-367
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 5, 2025CVE publishedPublication date reported by the CVE source.
  2. Sep 5, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0f314f6c2e77beb1a232be21dd6be4e1849ba5ac <1c2769dc80255824542ea5a4ff1a07dcdeb1603f
  2. Affected versionversion=0f314f6c2e77beb1a232be21dd6be4e1849ba5ac <2964dbe631fd21ad7873b1752b895548d3c12496
  3. Affected versionversion=0f314f6c2e77beb1a232be21dd6be4e1849ba5ac <3c3e33b7edca7a2d6a96801f287f9faeb684d655
  4. Affected versionversion=0f314f6c2e77beb1a232be21dd6be4e1849ba5ac <6aaef1a75985865d8c6c5b65fb54152060faba48
  5. Affected versionversion=0f314f6c2e77beb1a232be21dd6be4e1849ba5ac <7af160aea26c7dc9e6734d19306128cce156ec40
  6. Affected versionversion=0f314f6c2e77beb1a232be21dd6be4e1849ba5ac <ed905fe7cba03cf22ae0b84cf1b73cd1c070423a
  7. Affected versionversion=0f314f6c2e77beb1a232be21dd6be4e1849ba5ac <fbc81e78d75bf28972bc22b1599559557b1a1b83
  8. Affected versionversion=0f314f6c2e77beb1a232be21dd6be4e1849ba5ac <ff9dd3db6cd4c6b54a2ecbc58151bea4ec63bc59
  9. Affected versionversion=4.12

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=0f314f6c2e77beb1a232be21dd6be4e1849ba5ac <1c2769dc80255824542ea5a4ff1a07dcdeb1603f; version=0f314f6c2e77beb1a232be21dd6be4e1849ba5ac <2964dbe631fd21ad7873b1752b895548d3c12496; version=0f314f6c2e77beb1a232be21dd6be4e1849ba5ac <3c3e33b7edca7a2d6a96801f287f9faeb684d655; version=0f314f6c2e77beb1a232be21dd6be4e1849ba5ac <6aaef1a75985865d8c6c5b65fb54152060faba48; version=0f314f6c2e77beb1a232be21dd6be4e1849ba5ac <7af160aea26c7dc9e6734d19306128cce156ec40; version=0f314f6c2e77beb1a232be21dd6be4e1849ba5ac <ed905fe7cba03cf22ae0b84cf1b73cd1c070423a; version=0f314f6c2e77beb1a232be21dd6be4e1849ba5ac <fbc81e78d75bf28972bc22b1599559557b1a1b83; version=0f314f6c2e77beb1a232be21dd6be4e1849ba5ac <ff9dd3db6cd4c6b54a2ecbc58151bea4ec63bc59; version=4.12

Published CVSS scores

4.7NIST NVDCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
7.0Amazon LinuxCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-367Time-of-check Time-of-use (TOCTOU) Race Condition

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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